Case report: multiple endocrine neoplasia type 2B misdiagnosed as familial dysautonomia.

BACKGROUND: Familial dysautonomia (FD) is a rare autosomal recessive disorder of the peripheral nervous system, affecting exclusively Jewish children of Ashkenazi extraction. The typical clinical features consist of somatic abnormalities: failure to thrive, characteristic facies, excessive sweating, labile blood pressure, recurrent aspiration pneumonias, lack of tears, and diminished and later absent deep tendon reflexes with generalized reduction of pain sensation. Oro-dental features include a lack of tongue fungiform papillae, impairment of taste, oro-dental self-mutilation, dental crowding, excessive plaque and calculus accumulation, salivary over production and low caries experience. CASE REPORT: A child with multiple endocrine neoplasia type 2B (MEN 2B) received, at the age of 11 months, an incorrect diagnosis of familial dysautonomia (FD). At the age of 6 years, a paediatric dentist experienced with FD noticed a normal number and shape of tongue fungiform papillae, while expecting to find a smooth tongue lacking those structures. The presence of numerous submucosal neuromata initiated a meticulous neurological and endocrine work-up, which established the diagnosis of MEN 2B. This led to an early detection and appropriate treatment of asymptomatic medullary thyroid carcinoma (MTC).